Pure Mycelium Sheets from Edible Mushrooms for Sustainable Packaging: A Comparative Assessment of Glycerol and ZnONPs Treatment

Abstract

Increasingly, mycelium-based biomaterials are being investigated as sustainable alternatives to conventional packaging materials, but their inherent brittleness limits their practical application. The present study investigated the properties of pure mycelium sheets sourced from Ganoderma sp., Lentinus sp., and Pleurotus sp., employing glycerol plasticization and zinc oxide nanoparticles (ZnONPs). The findings revealed that growth and structural attributes varied according to the species, with Ganoderma and Lentinus exhibiting enhanced colonization rates. Scanning electron microscope (SEM) examination indicated that Lentinus developed dense fiber networks, Ganoderma exhibited compact structures, while Pleurotus presented a porous morphology. Glycerol enhanced flexibility but diminished tensile strength, while ZnONPs offered marginal reinforcement. Lentinus exhibited the greatest density, whereas untreated Ganoderma exhibited the highest thermal stability among the control samples (284.97 °C), while glycerol-treated Pleurotus exhibited the highest thermal stability overall (287.39 °C). Glycerol-treated sheets demonstrated improved ductility and heightened hydrophilicity. The properties of mycelium are species-dependent and can be modulated through targeted post-treatment strategies. Lentinus and Ganoderma exhibit significant potential as sustainable bio-based materials for packaging applications. These findings demonstrated that Lentinus sp. treated with glycerol achieved the optimal balance of flexibility and density for sustainable packaging, while glycerol-treated Pleurotus sp. exhibited superior thermal stability.